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Biogeography of Devonian vertebrates

1981; Taylor & Francis; Volume: 5; Issue: 3 Linguagem: Inglês

10.1080/03115518108567003

1752-0754

Gavin C. Young,

Scarabaeidae Beetle Taxonomy and Biogeography

Five faunal provinces based on vertebrates are proposed for Early Devonian time, as follows: a cephalaspid province (Euramerica), an amphiaspid province (Siberia), a tannuaspid province (Tuva); a galeaspid-yunnanolepid province (South China), and a wuttagoonaspid-phyllolepid province (East Gondwana). It is suggested that certain major groups of early vertebrates differentiated in isolation on these continental areas as freshwater environments were invaded, and the interrelationships of some agnathans and placoderms endemic to these areas are analyzed using the cladistic vicariance biogeographic method of Platnick & Nelson (1978). Two possible episodes of biotic dispersal are identified; between Laurentia and Baltica at the end of the Silurian, and between Gondwana and Euramerica during the Late Devonian. Amongst placoderm fishes a Gondwana origin is suggested for Phyllolepis, antiarchs indicate affinity between Gondwana and South China, and euarthrodires may have evolved in Euramerica. Phylogenetic analysis of other test groups is required to resolve conflicting evidence of area interconnections provided by agnathans and placoderms, and to establish the existence of general patterns in the Devonian distribution of endemic vertebrate taxa.